Concrete-pipe joint



PATENT OFFICE.

JOSEPH A. DUNN, OF IN 'DIAITAPOLIS, INDIANA.

CQNCRETE-PIPE JOINT.

Application filed February 27, 1925. Serial No. 11,941.

My invention relates to an improvement 1n olnts for concrete pipes and relates articularly to a concrete pipe joint whic is designed to stand an internal pressure, and which is water-tight, and to the recess of 1ts formation. Other objects Wlll appear from time to time in the course of the speci fication and claims. t1on more or less diagrammatically in the accompanying drawings wherein- Figure 1 is a longitudinal section.

Figure 2 is a longitudinal section on an enlarge scale of the completed joint; and

Flgure 3 illustrates'a step in the process of the formation of the joint.

Like parts are indicated by like characters t roughout the specification and drawings.

AA are concrete pipe sections each having at one end the bell member B and at the opposite end the spigot member C. In the form herein shown the bell and spigot members engage as at D along a plane slightly inclined to the axis of the pipe. In order to allow for irregularities and variation in sizes of the pipe sections and to insure a contact along the plane D I provide a clearance between the outer end B of the bell and the opposed ledge C at the base of the spigot.

The spigot member C terminates well short of the ledge B at the base of the bell member, in a curved surface C to which is tangent the ledge C The transverse face C, substantially perpendicular to said ledge, bounds the aperture between ball and spigot. It will be noted that the space bounded by the plane face B and the curved face G increases outwardly from the inner face of V the pipe, the result being thus obtained that the cement or concrete inserted therein, after it hardens, cannot become loosened and break away or drop into the interior of .the pipe. On the ledge C and abutting against the face C I compress a ring E of oakum or any other suitable packing material, which is preferably rammed into place after the pipe is set in position, for example by the packing tool E with its curved inner end E When the ring is once packed into place it tends to remain in position, since the space formed by the faces C and C and the opposite surface of the bell B is narrower at its outlet than at its base. Under some conditions it may be desirable to wrap the oakum or other packing about the ledge I illustrate my inven C before the pipe sections are placed in position, but I prefer to tamp or caulk the packing into position by means of the caulking tool, as shown in Figure 3.

In the smaller sizes of pipe the closure may be completed y troweling cement or I concrete into the remaining aperture, thereby holding the packing firmly in position, and closing the inner wall of the pipe. With the larger sizes of pipe however I prefer to employ a preferably flexible strip or closure, herem shown as the flexible strip or band G, to close the aperture between the faces B and G I then pour the cement into the aperture for example through a space B cast or broken in the bell B. In practice I prefer to trowel in the cement about the lower portion of the joint and to employ the band G in pouring the cement into the upper portion of the joint.

Under some conditions it is preferable to paint one or both of the opposed members with a coating of asphalt or other suitable material before tamping or caulking the oak:

um or packing into position. This coating or wash may be bituminous, and viscous, or may merely consist in a cement wash'of any suitable type. This layer preferably overlies not only the seat of the ring of packing but also the opposed surfaces of bell and spigot, as shown at KK in Figure 2. Elther one or both of the opposed bell and spigot members may be so treated. The result is an extremely tight joint, if the oakum 1s tamped into place while the asphalt or other material used is still hot or wet and relatively soft.

It will be realized that while I have lllustrated a practical and operative joint, and have described a practical process for forming it, that nevertheless I do not w1sh to limit myself specifically to the jo1nt and process herein described and shown but that many changes may be made in form and disposition of the parts and in the details and order of the steps of the process without departing from the spirit of my invention. I wish my description and drawings therefore to be taken as in a broad sense illustrative rather than as limiting me to my specific showing.

I claim:

1. A joint formed by the combination of overlapping bell and spigot members at the opposed ends of abutting pipes, which conslsts of ,a packing seated against both of ity of the aperture between bell and spigot,

and a ring of concrete engaging and confining said packing, the spigot memberv terminating in an inwardly curved surface, its inner surface being broken intermediate its ends by a" ledge adapted to receive said packing.

2. A joint formed by the combination of overlapping bell and spigot members at the opposed ends of abutting pipes, which consists of a packing seated against both of said opposed members, at the inner extremity of the aperture between bell and spigot,

and a ring of concrete engaging and confining said packing the spigot member terminating in an inwardly curved surface, its inner surface being broken intermediate its ends by a ledge adapted to receive said packing, the space defined by said ledge and by the opposed face of the bell being narrower at the outside than at the inside of said ledgei Signed at Chicago county of Cook and State of Illinois, this 13th day of February, 1925.

JOSEPH A. DUNN. 

